simple tree

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
  </style>
</head>

<body>
  <script>
    // Feel free to change or delete any of the code you see in this editor!
    var svg = d3.select("body").append("svg")
      .attr("width", 960)
      .attr("height", 500)
  var g = svg.append("g").attr("transform", function(d) { return "translate(" + 00 + "," + 100 + ")"; })
var tree = d3.tree().size([300,300])
.separation(function(a,b){
  return 1;
})
var stratify = d3.stratify().parentId(function(d){
  return d.parent
  
})

d3.csv("data.csv", function(error, data) {
	 //console.log(data)
  var root = stratify(data);
  var nodes = tree(root)
  
  
 var link = g.selectAll(".link")
    .data(root.links())
    .enter().append("path")
  	.attr("fill","none")
  .attr("stroke","black")
      .attr("class", "link")
      .attr("d", d3.linkVertical()
          .x(function(d) { return d.x; })
          .y(function(d) { return d.y; }));
  
  
  var node = g.selectAll(".node")
  .data(root.descendants())
  .enter()
  .append("g")
  .attr("class",".node")
  .attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; })
 node.append("circle")
  .attr("r",10)
  .attr("fill","#fff")
  .attr("stroke","black")
 
 
})

</script>
</body>

https://d3js.org/d3.v4.min.js